The invention concerns a method for controlling a transfer device in a packaging machine, wherein the transfer device comprises a first conveying device which is moved in cycles, a second conveying device which is moved in cycles and extends, at least in sections, parallel to the first conveying device, and a pushing device which performs a pushing motion substantially perpendicular to the transport direction of the conveying devices, wherein a product is supplied to a transfer location via the first conveying device, transferred to the second conveying device by the pushing device during a standstill phase of the two conveying devices, and is subsequently further transported via the second conveying device, wherein the pushing device is in a withdrawn position outside the path of motion of the product disposed on the first conveying device, and, in an insertion position, at least partially extends over both the first conveying device and the second conveying device.
The invention also concerns a transfer device in a packaging machine, comprising a first conveying device which is moved in cycles, a second conveying device which is moved in cycles and extends at least in sections parallel to the first conveying device, and a pushing device which performs a pushing motion substantially perpendicular to the transport direction of the conveying devices, wherein a product can be supplied to a transfer location via the first conveying device, transferred to the second conveying device by the pushing device during a standstill phase of the two conveying devices, and further transported via the second conveying device.
Products must be relocated between two conveying devices of a packaging machine, or transferred from one conveying device to a second conveying device. The conveying devices are usually endless circulating conveying belts or chains which are moved in cycles. In the following example, the first conveying device is the so-called product chain for supplying a product to a transfer location, and the second conveying device is the so-called folded box chain for supplying a package or a folded box to the transfer location. The invention is, however, not limited to the above-mentioned conveying devices, but can also be applied to different types of transfer of a product between two conveying devices, which are driven in cycles, within a packaging machine.
The product chain sequentially supplies a continuous row of a plurality of similar products to the transfer location. A plurality of erected, similar folded boxes are correspondingly sequentially supplied in a continuous row to the transfer location via the folded box chain. The cycled drive motions of the product chain and the folded box chain, which extend parallel to each other at least at the transfer location, are synchronized by using a common drive, such that, at the transfer location, the product can be pushed from the product chain onto the adjacent folded box chain by a pushing device during a standstill phase of the drive motions, and be pushed into the open package at that location. As soon as the pushing device has returned into its withdrawn rest position and is positioned outside of the path of motion of the product chain and the folded box chain, the two chains are advanced and moved on by one motion cycle.
Modern packaging machines operate at very high cycle rates, such that one working or motion cycle may take only a few milliseconds. The packaging machine is consequently subjected to relatively great dynamic loads, since the masses to be moved must be quickly accelerated, decelerated, and stopped. In particular, the folded box containing the product may have a relatively large mass which produces vibrations resulting in unstable operation of the packaging machine during operation at high cycle rates.
Handling of the package containing the product subsequent to product transfer, i.e. downstream of the transfer device, may also be problematic due to the relatively short cycle times, since subsequent closing of the package requires a highly dynamic closing motion and only a very short time is available to remove the package containing the product from the packaging machine.
In order to eliminate the above-mentioned dynamics problems, the cycle rate has been reduced, thereby reducing the speed of motion of the product chain and the folded box chain with the disadvantageous consequence that the efficiency of the packaging machine is greatly reduced.
It is the underlying purpose of the invention to provide a method for controlling a transfer device in a packaging machine which reduces the dynamic loads in the packaging machine without reducing the efficiency of the packaging machine, and a transfer device for performing the method in a simple fashion.